1. Field of the Invention
The present invention relates to a bending operation apparatus for an endoscope that is provided in an operation portion of the endoscope, and causes a bending portion of an insertion portion of the endoscope to bend.
2. Description of the Related Art
In recent years, endoscopes have been widely used in medical fields and industrial fields. The endoscopes for use in the medical fields are capable of observing organs in body cavities and performing various treatments with use of treatment instruments inserted into insertion channels for the treatment instruments that are included in the endoscopes in accordance with necessity, by elongated insertion portions being inserted into body cavities that are subjects.
Further, the endoscopes for use in the industrial fields are capable of performing inspection such as observation of flaws, corrosion and the like of sites to be examined in objects and various treatments, by elongated insertion portions of the endoscopes being inserted into objects such as jet engines and piping of factories.
Here, a configuration in which a bending portion bendable in a plurality of directions is provided at the insertion portion of an endoscope is known. The bending portion not only enhances the advance ability of the insertion portion in a crooked portion in a duct, but also makes the observation direction of an observation optical system variable, the observation optical system being provided at a distal end portion located at a distal end side in an insertion direction from the bending portion, in the insertion portion.
Normally, the bending portion provided at the insertion portion of an endoscope is configured to be bendable in four directions, up and down, and left and right, for example, by a plurality of bending pieces being connected along the insertion direction of the insertion portion.
Further, the bending portion is bendable in any one of the up and down and left and right directions, by a bending operation apparatus, which is provided in the operation portion, performing a pulling operation of any one of four wires which have distal ends fixed to the bending piece that is located at the most distal end side in the insertion direction out of the bending pieces, the wires being inserted through the inside of the insertion portion.
More specifically, the bending portion has a configuration in which a bending operation knob for vertical bending that is provided in the operation portion is rotationally operated, whereby a sprocket for vertical bending that is provided in the operation portion is rotated, any one of an upper side chain site and a lower side chain site of a vertical bending chain that is wound around the sprocket is pulled, whereby any one of the upper and lower wires is pulled, so that the bending portion is bent in either an up direction or a down direction.
Further, the bending portion has a configuration in which the bending operation knob for lateral bending that is provided in the operation portion is rotationally operated, whereby a sprocket for lateral bending that is provided in the operation portion is rotated, and any one of a left side chain site and a right side chain site of a lateral bending chain that is wound around the sprocket is pulled, whereby any one of a left and a right wires is pulled, so that the bending portion is bent in either a left direction or a right direction.
Further, the configuration is known, in which the operation portion is provided with a vertical bending fixing lock lever that fixes the bending angle of the bending portion that is bent in an up direction or a down direction by a rotational operation of a bending operation knob for vertical bending, namely, a rotation position of the bending operation knob for vertical bending. Furthermore, a configuration is also known in which the operation portion is provided with a lateral bending fixing lock knob that fixes the bending angle of the bending portion that is bent in a left direction or a right direction by a rotational operation of a bending operation knob for lateral bending, namely, the rotation position of the bending operation knob for lateral bending. The configurations are disclosed in Japanese Patent Application Laid-Open Publication No. 2000-152912, Japanese Patent Application Laid-Open Publication No. 7-261098 and Japanese Patent Application Laid-Open Publication No. 10-295628.
Furthermore, Japanese Patent Application Laid-Open Publication No. 6-327616 discloses the configuration in which a locking member that prevents unintentional motion of the fixing operation member is provided in either the operation portion of an endoscope or the fixing operation member.
Furthermore, Japanese Patent Application Laid-Open Publication No. 2004-351221 discloses the configuration in which with use of an O-ring, the fixing operation member and the bending operation knob simultaneously rotate.